Art of fiber liberation



Sept. 6, 1938. J. H. ESTES ART OF FIBER LIBERATION Filed June 29, 1952 vPatented Sept. 6, 1938 UNITED STATES PATENr ermee 1o claims. I(ci. ca -1c) This invention relates to improvements in the art of fiber liberation and in' flbrilized products thereof.

More particularly the invention involves the 5 treating of ber with aliquid composition which, by reacting chemically with certain parts of the ,fiber,"and by avoiding reaction with cerl tain other partsmakes at low cost a brilized product having new or greatly improved properties.

Theinvention deals Lwith the mutual relations of ultimate cells of the ber; and it provides for their selective and limited separation, viz., separating certain ultimate cells from certain other w ultimate cells which lie adhesively at microscopic distances beside them; and it provides for the doing of this without injury to either of the said separated cells, and without breaking or weakening the endwise adhesions of such cells. The successful achievement of this selective control has brought with it the promise of great benefit to industry andthe arts. The .treatment is herein described with reference to what are known to commerce as long vegetable bers. Having`V` successfully applied the invention experimentally to a' great number of such, both of bast and of leaf origin, it appears to me probable that the invention is applicable with vbenet to all bast and leaf bers. And it has also been applied with advantage to some other kinds of plant ber.

Preferably the invention is applied to the "fiber after any customary or suitable retting or decorticating process; that is', after the cortexl as and woody portions of the stalks, or the pulp in case of leaf ber, have been removed.

In ber seen at this stage, or after the fur ther processes practiced to prepare it-for spinning, that which the eye observes as a typical one 40 oi? the separate -laments, however` small, is never- 'theless an aggregation -of vsmaller lamental elements (fibrils) whose lndiviauai'iaentity is pracmay contain few or many fibrils. The tubular bril cells are of microscopic diameter,of the order of one to two one-hundredths of a millimeter in many kinds of plants. But they differ greatly in length, ranging from one or two millimeters, in some kinds of plants, to twenty or more centimeters in others. The invention provides for removing, from the microscopic interstices, cementitious matter which intervenes laterally between cells, thus freeing the fibrils from each other; 'without at the same time weakening the endwise cementitious connections of the cells; and without chemically degrading the y tubular walls of the cells;A thus leaving the freed fibrilsindividually intact and strong,

from the original heterogenous material may contain, in some instances, cells of other variety than that above described, e. g. cells which are not ordinarily in a strict sense considered to be Dart of a iibril, although the string be comparable to one or a small number o fibrils in diameter. l'. vtherefore call theinvention a iibrilizing process,

and the ber-bundle fragments splits- The improvement by. which l have accomplished this involves the excluding of caustic and other strong alkali from the treatment; the excluding of acid; the making of a colloid which is so perfectly a hydrophilic colloid that it.. can penetrate fully'the microscopic interstices and thus thoroughly can wet the heterogeneous materials that make up the ber, and is of such composition that it can serve as a protective colloid tor a selected portion of the ber; the making of an alkali reactive solution whose notable and essential characteristic lis that its valkali is extremely weak, within limits; the supplementing of this, for certain kinds of bers, with a sodium' sulfite characteristic; yand the careful control, according to certain principles, of the conditions and duration of-application of the solution to the iiber.

The accompanying drawing, which is more or Jless diagrammatic, illustrates the invention lby, showing plant and ber structure on the basis longitudinal and transverse section through suoli` a ber bundle; and

Figure i is a schematic `drawing on a still larger scale, large enough for details to be shown sisal.

indicating the three kinds of material between which the selection is made, and representing at A, a fragment of a ber", in side elevation, at B a similar' fragment in section corresponding to the longitudinal portion of Figure 3; and at C.I

and D the split condition at successive stages of treatment, viz., at C a portion of such a fragment upon which the process of the invention has operated to a certain extent, suicient to free some of the ultimate cells of their lateral junctures, making separated brils; and at D a portion of such a fragment on which the reaction has proceeded further, so that the lustrous cellulose of each ultimate cell is cleaned of all of its lateral surrounding lamellae ci cementitious matter, but remains with its own cell walls and its Aendwise cementitious iunctures intact, having fully withstood the chemical attack.

Figure 5 represents a cross section through a. fragment of a stalk of angreatly enlarged, with introduced heavy outlines indicating ber hun? dles such as customarily constitute spinning units or laments; and

Figure 6 represents similarly a fragment of a stalk of jute, in the bast region, showing by introducedfheavy outlines the agglomerated bundles of bast ber, each bundle representing. a spinning unit or lament. Y

Figure '7 represents a bril of ramie, as it appears when seen microscopically, having knobs, between which bends have been made, giving kink to the bril;

Figure 8 showssimilarly a typical development therein have been made prominent by the treatment.

Figure l shows a typical ber-bearing leaf of a kind of plant (in this instance sisal, Agape sisalanc) whose ber is strong and long but vhas hitherto been used mainly' for coarse work, as cordage, because it bas not been capable of economical sub-division for ne work. The epidermis lil surrounds a pulpy mass of parenchymous tissue I2 in which are embedded a mul- `titude of ber bundles I4. Any one of these bundles Ill is a lamentary unit as now cus'- tomarily used in industry, called a ber" of But each ber is really a closely agglomerated group of numerous brils, vas representedin Figure 2. By the invention this group can be handled in mass with others as a mass of bers and Aeach ber in the mass be indi- `inually fractioned into sub-groups of its brils,

dr eveninto 'its' individual brils. These brils consist of relatively long tubular cells, Figure 3, the lengthv of cell, in the case of sisal, being' one hundred times the cell diameter. `l3nt as that proportionately great length really amounts' to only 2.5 vmillimeters (the average for sisal) it is clear that a separation of cell from cell in the individual bril would not leave a unit of practicable length for spinning into a. strong thread. The cells I5 are of cellulos, hard and strong, with walls thickened by interior growth so that they are called sclerenchymous. Other kinds of long cellulose cells seen in these gures are the bundle sheaf cells I6, phloem or bast cells II, and the tracheids or wood cells I8. 'I'he envelope of starch cells I9 is of no industrial importance; but the vvarious cells l5, I'I, I8 have permanent value. In the plant, and in the ber bundle after its preparation treatment for spinc ning, as applied hitherto, they remain still cemented together inv their bundle.

Figure 4 illustrates schematically the relative arrangements of adjacent brlls in leaf bers, and will serve equally to indicate the same for bast or stalk bers. `However, it should be noticed that, for convenience of illustration, the lateral dimensions are exaggerated, as to thickness of llirig between cells; and that the number of cell-ends represented is greater than would 'ordinarily occur in the length.of ber which is portrayed. Microscopic investigations of structure, aided by differential staining, have shown the cells I5 surrounded by cementitious lamellae whose chemical character varies progressively as one proceeds outward from the pure cellulose of the cell wall, whether proceeding outward laterally oi the cell or endwise of the cell. It is the purpose and effect of the invention 'to remove the middle lamella I3 and more or less of its adjacent lamellae also marked I3 whichiintervene between cells l5, in order to release the cellsl I5 from their mutual lateral attachment:

and yet to avoid'removing or substantially weakening those bits I I of cementitious material whichA stand between any cells I5 which. lie end to end. The latter constitute endwise junctures `makingy a longitudinal succession of cells into a bril.

Both deposits of cementitious matter II and I3 usually consist of pectic substances of various kinds, except that in ysonie kinds of plants Il sometimes has strong ligneous characteristics.

Figure 5, illustrating the bast region of a stalk of ax shows the epidermis 50 of the cortex which surrounds the mass of parenchymous cells 52 in which are found the bundles 54 of sclerenchymous cells, which bundles, survive the retting process. The heavy lines around'the bundle are introduced to indicate thexlimits of the bundles portrayed, each of whichy bundles, inordinary practice, may constitute a ber or lamentary spinning unit of ax or linen.

Figure ii is similarly a portion of a. cross secl' The coarseness f fabric woven from jute, as burlap, is well known. 'I'he invention, by brilizl ing the bundles 34, splittingthem intov smaller groups or into individual brils, makes from jute a spinnablev brous product `from which cfoth l can be made of very different aspect. because the separatel laments are so-soft and exible.

Fiber bundles of other stalks and leaves, which the process of the invention can likewisev split,

producing industrially available'laments having the improvedV qualities'herein indicated, are typied by these showings notwithstanding the divergences which exist between kinds of plants, and sometimes between grades of ber from the samekind of plant. Thevprocedure of the ini vention is to attack the middle lamella Il, il or 33 with a weak alkali capable of moving it by solution and/or chemical attack; while retarding the-chemical attack on the cell wall I5 and its more intimate enclosing lamellae which the4 chemicals used are capable of affecting; and while avoiding the use of chemicals which might attack the materials constituting the endwise juncture ii between cells. As the effects must be gained by penetration by the -protectingmaterialalong with the attacking material into spacesof extremely small dimensions. a first requisite is the making of a colloid whose continuous phase (in this case water) will be perfectly adsorbed on interstitialvsurfaces and which is so perfect a colloid that its dispersed phase neutral soap) will follow in for giving the desired protection.

For the making ofsuch a hydrophilic colloid I have found it satisfactory to put finely divided Well dried neutral soap into water which is boiling. The boiling water has a temperature and a concomitant agitation which will assure th making of a hydrophilic dispersion if the quantity between .2 and .5 of of water. With a percentage'of soap higher than l 1% there is probability of making a hydrophobic in the weak hydrated form called sal soda where-v in each molecule is associated with ten molecules mixture or, at any rate, a mixture which does not penetrate among fibrils completely and operate uniformly. With less than the proportion stated, the desiredhydrophilic colloidal state may not arise. "If the soap be put into cold water which is later heated there is also `danger' of missing `-`rthe desired result. because the soap may become hydrolized. But the making of a hydrophilic colloid as stated evidently carries the soap thoroughly into the interstices -between ilbrils, as openings between them'become available during the treatment, and protects the cells from the attack of the alkali of the solution.

For the alkali I prefer to use sodium carbonate of water; and of this crystalline. substance I take a quantity in the range between .9 of l per cent and 1.3 per cent of the quantity of water into which it is to be put. ,The equivalent range of anhydrous sodium carbonate would be from a thir'd to a half of one per cent.'and this is the strength or concentration of alkali in the liquid which that amount of sal soda produces. This,

like the soap, is 'to be ground fine and put into.l

the boiling water.

Preferably the soap land the alkali should be ground and mixedpreliminarily, to be put into the water together, for experiment has shown 'me that the process works less well when the chemicals are not'pre-mixed.

The fiber, preferably 1in vquantity weighing about 5 or 10 per cent of the water, maybe put` into the boiling liquor thus prepared, and the vigorous boiling continued in an open vesselv for about a half hour. Boiling in a kier or a cl vessel is to be avoided,as not providing a desired access of atmospheric oxygen.

' agent be added in a closed vessel the results are likely to be not uniform.

The fiber is to be removed from the boiling liquid when it can be ascertained, by rubbingfa sample between the lingers, that its initial harsh 'feeling has changed to a slimy, slippery, soft and silky feeling.,. Over a wide range of fibers I have found that the proper duration of boiling ranges (in this case aof soap put in beof a proportion ranging one per cent of the quantity between 25 anda-1 5 minutes; and that the stated half hour is about right for most fibers.

Upon removal from the liquor the ber is to be rinsed. drained and dried.

If treatedvwith acid the product will lbe weakened, or even broken into short lengths.

weakening may also result from having alkali too strong in the liquor. And, if treated toio long by thespecifled proper liquor, the b'er will lose in strength, which is due presumably to progress by the alkali in converting 'cellulose of the cells I5 to'oxycellulose which is brittle. This converting reaction is` retarded by that quality of the protective colloid which draws it to the surfaces of the cell, and thoroughly wets those surfaces, and adsorbs the protective film of neutral soap strongly thereon. Coupled with this are the concomitant weakness of the attack of the alkali on the cellulose', because of the low alkali concentra tion; and theconstant progress meanwhile,-dur 2@ .lng this retardation, of the business of removing the alkali-soluble pectic bodies. As the chemical reaction with and/or solution oi!v these pectic bodies progresses, parts of 'the middle lamellae disappear, and thus therm lateral junctures between -cells diminish, Progressively the ultimate fibrils come tobe only weakly connected to each other, a state in which they may later be` come separated by mechanical rubbing;v and progressively entire separations occur as the action of the liquor continues. separations rstoccur by breakages through weakerplaces in the midst 'ol a. .fiber bundle, leaving the bundle in split tinuing it still `longer to get sub-division into individual fibrils. But in each case the retention by the cells of their native tensile strength, and their endwise connections, leavesthem workable as long iilaments (fibrils). These retentions of i length and strength are important features which distinguish the product of they present invention. y f

The explanation underlying this ,important feature is, I believe, that some among the numerous kinds of pectic bodies, which are present in plant stalk and leaf iibers, are soluble in acid, and some in alkali. It is known however that wood ber can be broken into elements short venough for making paper by either acid alone lor by soda alone. .Alkali attacks cellulose, converting-it to oxyeellulose by adding oxygen; and the tubular walls of the ultimate cells i5, 35, 55 consist of cellulose, oi microscopie thickness. However,`it happens that those pectic cementitious which stand laterally between the ber cells are the ones capable of being taken into solution by thetreatinent with very weak alkali above described; 'whilethose pectic cementitious bodies which connect the ultimate cells endwise resist alkali. They yield to acid. But because caustic y alkali is excluded from the itormula provided by the invention; and strong concentrations of soda bodies middle lamelle. before damaging eiect upon the cellulose has become appreciable.

'Ihe selectivity of action is especially important'- in dealing with kinds of fibers which have not hitherto been sub-divisible Without sacriilce'of strength, because some of such are inherently 'much longer and stronger and are at the same l l time less costly than the kinds of ber commonly Some ilbers are not completely flbrilized by the'treatment above set forth. This depends upon the nature of the piani-.and to some extent the age or toughness of the individual plant. For unusual toughness the concentration of alkali maybe increased and used near the higher limits stated, where the ber is of a. kind with v which the above treatment is usually satisfactory.

These include jute, pita, sisal, ramie, flax, hemp,- bear grass, Furcraea macrophylla, Mauritus hemp, Colombian smooth leaved pita. bow string "hemp: and for these the above formula of mild. carbonateconcentration with a protective coiloid will satisfactorily sumce.l

But in some kinds of plants the cementitious Y Amaterial which stands laterally of the ultimate cells in a fiber bundle has a. ligneous component such that it is not sumciently removed by a weak alkali solution as defined above. 'I'hese include manila, New .Zealand dan, lowest grade sisal (butts and aged stock), cabuya, Colorado River hemp, and other very strong fibers which have never heretofore been made available on a commercial scale for nne spinning so far as I am aware, because of inability to make the subdivision.

. For the successful dealing with such it has been discovered that the process operates best when the described liquoris supplemented by addition When the crystalline sodium carbonate is usedthe following proportions serve: A

' v Per cent Neutral soap. well dried .2 to .5 Sal sodal .5 to l sodium sulphie .2 to .'15

These are to be preliminar-ily ground and mixed together and then put into boiling water 100%.

. In the liquor thus formed the fiber is to be boiled vvigorously until a suilicient removal of the lateral cementitious material is discernible bythe test- 'ing of a sample by feel as above described.

Ii' the formula be' varied by using the sodium` carbonate in the form of the` monohydrate NazCOzHzO. its percentage relative to the water would be in the vicinity of .3 to .8% of the water: or, if used in the anhydrous form of soda ash NazCOa, the range of about .2 to .7% of the water into which it is put wouldbe equivalent to the preferred formula.

The desirability of excluding caustic alkali having been explained above, in 'order to avoid l having such character or strength of alkali as will appreciably attack thecellulose, it remains to mention two exceptions; first, that such ini nitesimal degree (if any) of hydrolysis as occurs. incidentally upon the putting of sodium carbonate into aqueous solution has no appreciablev eect, and may be treated as a nonentity. Second,'a weak concentration of sodium hydroxide 5 may rwbe safely employed to provide the,desired alkalinity, if this be in conjunction with the sodium sulte, because the latter acts as a retarding agent, and in effect renders nugatory the potential attack of the caustic on the cellulose. l0

In that case the sodium hydroxide NaOH may be taken within the range of .l to .5% and sodium sulphite NazSOa Within about the range of .2 to 1%. Being ground and mixed together and put into 100%.of boiling water, a suflicient alkalinity l5 is present for dissolving the lateral pectic bodies, and sulphite for dissolving the ligneous bodies, without affecting the endwise cementitious matter of cells. But the tendency of the sodium hydroxide to degrade the cellulose into oxycellulose v is restrained because the sodium sulphite, acting as a reducing agent, seizes upon a large part of whatever oxygen is found in the liquid and so preempts it from use in a reaction with the cellulose.

The sodium sulphite has its best eiect of separating cells laterally when-.used in conjunction with weak alkali as herein set forth. This has the notable industrial benefit that it renders available, for fine spinning,-the fibers of various kinds of plants which are known to have especial meritsbut have not been thus available before. Obstacles have been the extreme diiiculty and high cost of getting them finely divided, if indeed this hasbeen possible at all except by the use of alkali in such strength as has disintegrated or too much, weakened the product. Among such are New Zealand ax, manila, cabuyfa', istie, lowest grade sisal.

The discovery has followed that the known 40 great strength of some of these tropical fibers can be retained in the sub-divided fiber and utiu lized in cloth and cords of very great strength as compared with the cotton and other fibers which have been the only material hitherto avail-` able for the desired sma1l`sizes. Applied in the manufacture of automobile tires, the cords may be both smaller andstronger. Applied in cloth thewoven fabric may be ne and exible; but also, because of the nature of certain fibers renderedavailable by the invention, and hitherto available only in harsh and coarse form, .as jute, manilaand sisal, cloth ay be made from these bers which proves to besurpassingly soft and silky. Such cloth may be close woven, and even 55 be tight against passage of air or water; greatly surpassing cotton and linen in strengthgand yet being less than cotton in cost.

An important matter from the industrial f standpoint is the getting of uniformity of product, as regards degree of sub-division. A feature of the processwhichH contributes to this is theMAN perfection of the hydrophilic colloid, and this is promoted both by the observance of the stated limits and the maintenance of a boiling condition 65 of the water when the mixture, is introduced. Another contributing feature is the maintaining of a condition oi' vigorous ebullition during the treatment. This tends to equality of application of the processto .all 'parts of the ber.

. The treatment may be stopped' when the described stage has been reached as between some but not all of the fibrils of a bundle. The ber bundle will then be fractioned into smaller. groups of ilbrils: and for some industrial uses this will be suiilcient and be even better than the extreme sub-division which is obtainable by continuing the treatment till all individual fibrils are separated.

In the plant stalk whose ber is to be used, the said liber bundles stand in the. bast region, aroundthe pith and/or woody center; and the whole is surrounded by the cortexv orbark-like these steps merely segregate the fibers (bundles i4, 34, 5d) from unwanted matter. Such partial success as may have been attained in splitting bundles, whether by long continued bio-chemical decay in the retting, or by treatment in boiling solutions of alkali and/or acid, or by maceration, has been always, I believe, accompanied by injury to and deterioration of the fibrous product, and has resulted in the weakening of the cellulose cells, or their endwise junctions.

The fibrilized product of the present' invention is distinguished from all such by its cells being of their original strong quality of cellulose, their endwise junctures unaffected, and their physical lstructure unimpaired by crushing, inacerationv or breakage.

y .The surfaces ofr cleavage left on the elements separated bythe invention will be, in some cases,-

the pure cellulose surfaces of the individual cells in the fibrils, as in Figure 4-D. If the eroding treatment be carried less far, the cell surfaces may retain some of their surrounding cementi-A tious lamellae, as indicated by the rough lines in Figure 4-C, or indeed the process may have been stopped when the original bundle, splitting rst at its thinner or weaker places, had as yet separated only into group fragmentseach containing several iibrils. In either event the product is spinnable into finer threads than while the original bundlesxremained undivided. 4'And in either4 case the distinction is noted, over such fibers as iiax, for example, where reduction of the retted product is executed by various methods of bruising and fracture, that the unitary lament produced by the present invention has its cells andconnections substantially whole inlongitudinal extent, with separation and surfaces made gently by restricted erosion; and that the mass contents are homogeneous in form.

The' relative lateral thickness of cementitious matter is greatly exaggerated, in the drawing; andit is to be expected `that in ordinary commercial practice substantially the whole of this really very thin substance will usually b'removed from the outside of the .lamentary units produced by the iibrilizing treatment. Microscopic diametric measurements of fibrils freed-by the process of the invention, in certain experimentsmade under my direction over a wide range of kinds of fibers, have shown figures markedly less than the figures (measured from middle lamella to middle lamelle. as vthey lay in the retted fiber) published by previous investigators as diameters of the same kinds of fibers; This-indicates that,"

in the brilized product, cementitious matter Same.

being splits as indicated at Figure 1 -D, was

which was surrounding the cell laterally has been removed. v

Comparison for lossof weights indicates the 'I In an illustrative instance, the product,

found to have the same 'composition chemically as the ber had before treatment,except that the greater part of the pectic substances were absent; and-the fats, waxes and'gums were also absent. Before treatment the analysis showed:

'Per cent Cellulose 76.1 Pectic bodies 11.3 Ligneous matter 1.4 Fats, waxes, gums 5.4 Moisture 5.8

The pectic `substances are known diierential staining to be located mostly within the fiberbundie and between the brils, where they constitute the lamellaefof cementitious matter; and

`the fats, waxes and gums are mostly or whollyv outside of the liber-bundle. As left by the retting or decorticating process the fiber of a plant is frequently in units too still' and coarse to be handled well for spinning, because the ber units are agglomerations of bundles held together by the gums and waxes.

Therefore degumming. processes of various sorts are used to break these porous; and thus the eager wetting powers of the A soap dispersion are believed to have quick access to the cellulosewalls for their protective adsorption thereon. But if the agitative boiling be con tinued too long the progress of the alkali in degrading the cellulose is observable, with a marked reduction of strength of the cells andthe resulting product.

However thelboiling treatment may with ad-v vantage be continued beyond the stage .of erosion* of lamellae and separation into individual lultimate' fibrils. An extraten minutes results in the introduction of a new characteristic into the ilber,

viz., kinks, represented in `Figures 7, 8. and 9, which are comparable in effect to the kink. of wool, making the fiber, when spun, hold together better than heretofore, and so be easily s'pinnable intoner counts of thread. In the case of ramie.

Figure '7 this contrasts with ordinary ramie fibers, which without thistreatment are characteristically straight and smooth, and diilicult for textile use. And from this there results cloth'which in some respects closely resembles woolens, having qualities of kink, warmth, and great strength, but

being also insect proof and more absorbent of moisture than is`wool; and this cloth may be of very lightweight. threads can be used either alone or intermingled vals; and the kinks 12 arise from bends' whichr develop in the shaft of the cell between the knobs.

In jute and hemp (Figure 8) where no knobs are observed in the bril 80 (made up of cells 85 joined at 8l) .sinuousnforms 82 arise. In the case of these particular fibers, as the length of a cellv Thel kinked `ramie liberor- 85 is of the order of a hundred or a thousand times its thickness, breaks are made in the drawing so that successive ber junctures 8l can come into the picture with their cementitlous material intact. In some other fibers, Figure 9, it appears that knobs are present morphologically in the cell 95, and that they are developed as at 96 by the erosion of the cementitious lamellae surrounding them, corresponding to I3 of Figure 4, instances being seen in istie, sisal, and Sunn hemp. These effects tend to make the respective fibers more spinnable. y

Figures 7 8 and 9, as also Figure 4, have been drawn after careful observation of the working of the invention, and microscopic study, and represent the subject matter as the structure is believed to be. l

I do not know the explanation for the development of this kink, but I suggest the following as being probable: 'I'he cellulose wall of the flbril cell is uneven as regards thickness, and, when the surrounding cementitlous material has been .removed by the treatment, water of the solution acquires access to the cellulose wall, which, being a colloid, swells under the access of water and,

being uneven in thickness, swells unevenly, which' produces contortions. The presence of this kink, however brought about, and the development of protuberances, indicated in Figure 9, which are comparable in industrial results, and may for practical purposes herein be included under the general term of kink, is an extremely important element of industrial utility in that it enables these various kinds of fibers, hitherto relatively smooth, to become strongly inter-engaged when reduced to fibrils and spun, thus making strong threads, even though the count be very ne.

By removing pectins and the pectic lamellae which surround the ultimatev cells, the process of the invention incidentally removes whatever is adhering to those lamellae, and this includes the fats, waxes and gums, and any bits of bark, dirt, or oil, on the outside of the fiber-bundle. In so doingV it removes matters which attract insects because of their food value or furnish basis for obnoxious small plant growth, as molds and mildews. The absence of food values in the ber makes the products manufactured from the treated ber, as clothing, be therefore insect, mold and mildew proof, unless some other insect or plant food be added during later steps of manufacture.

Another effect of removing the lamellae while preserving the endwise junctures of ultimate cells is that i-t uncovers the color and lustre of the pure cellulose of the Walls of the latter. ,And this, because of the freedom from deteriorative matter above stated, appears to be capable of very permanent continuance. In particular it is not destroyed by laundering, as are mercerized effects. But this lustre is not obtained from such parts of the cellulose as remain covered; nor from such parts as become degraded into oxycellulose, by reaction with alkali; or into hydrocellulose if there were ammonia present;` or become pitted by erosion of the natural cellulose surface under the alkali attack, which is at work close by in its task Aof dissolving the pectic bodies. For the successful avoidance of such ill effects in the cellulose, the above described colloidal hydrophilic the time necessary for the desired operation) or so as to get at the cellulose and attack it effectively (within the time needed for practicable operation) Two of the bers named have a slightly different material in the walls of their ultimate cells, viz., jute, which has ligno-cellulose and flax, which has pecto-cellulose, but as all or practically all of the others have cellulose, and as the behavior of the cellulose and the pecto-cellulose and the ligne-cellulose is substantially the same, in the matters with which this specification deals, the term cel1ulose" is used in the claims to refer to them indiscriminately.

Another eiect of converting the liber to brillized form with the cellulose surface of the cell wall exposed is that the remarkable absorptive power of pure cellulose surface for water and aqueous liquids, as human blood, becomes available; and it is observed that the brillized product of various plant fibers as jute or ramie, masses of which nevervheretofore have been considered absorbent, are found to be very absorbent, more so, for example, than standard absorbent cotton. And likewise cotton, which is a seed hair, responds to the treatment above described for fiber-bundles by becoming more highly absorbent,-and this at a cost which, for the above described treatment, is markedly less than the methods at present customary for making absorbent cotton. Inasmuch as the methods hitherto known to me for making absorbent cotton have involved the use of caustic alkali and long boiling and no protective colloid for the cellulose surface, I think that the superior results of the process'which I have described above, when applied tothe seed hairs, may be due to the protection which the colloid renders against attack by mild alkali, in the one case, as contrasted with y,the defenseless condition of the cellulose surface against the strong attack of caustic alkali in the other case, so that the natural surface may have been degenerated or eaten away, as hitherto prepared.

Another observed characteristic of the flbrillized .product is the homogeneity of a mass of the bers which have been treated together, in the sense that the splits of the fiber-bundles display a marked uniformity of diametric. size and 'of surface and chemical characteristics,-to an extent which renders them distinctive in this respect among bast and leaf bers known to commerce and industry.

The product of the described treatment is likely to be in most cases merely a step-product, to be Afollowed by other steps of manufacture, as dyeing, spinning, weaving; yet in some cases, as where intended for use as an absorbent, the product of the treatment may be the nal form in which the ber is to be used. Therefore, inthe claims the general term produc is used to refer equally to a mere step-product, or indeed it may be, a piece of woven cloth, for the described treatment for fibrillizing the fibers is applicable whether before or after spinning and weaving, and the same is true of the process when` used for cleaning or otherwise treating other plant bers, as seed hairs.

So also the term decorticated is used with general signification to indicate a removal of bark or skin, and of wood, pith, pulp or other unwanted material to which the fibers are connected by nature, regardless of whether the particular method used be fermentative, chemical or mechanical; and this term does not imply a limitation to 'that stage immediately following the a larger proportion of the ravv materiaL'i. e. with decorticating, but may include later stages in which the fiber may already have been spun or yf'vwoven; and even the analogous cases where under a boiling condition of the liquid in the open l.

air; but this situation can be approximated at a temperature somewhat less than -boiling in ,which a strong and universal circulation of the liquid .among the fibers is promoted by other means.

The resulting lamentary fragments of fiberbundles'are convenientlysaid to be chemically split because the division occurs on the longitudnal) lines, and vthese filamentary fragments themselves are referred to as splits notwithstanding that the division v occurs by removal of material leaving a surface of erosion, as distinguished from the more ordinary `sense of the Word split which signifies a longitudinal fracture made by mechanical force of spreading and rending, leaving a surface of fracture.

.And the term catamorphosis" is used, by'. analogy from terminology employed in geology,4

to signify the breaking down of the form of the fiber by its splitting into fragmentsby erosion of lateral bonds between cells.

Statements of quality refer to weights, unljess otherwise expressed.

Although I have spoken in detail oniynf treating l fiber at the stage after its retting and before its combing, carding and spinningthe invention is not limited to that. It may for' example be applied to fiber which has already been woven into cloth; for. example, a sheet of ordinaryburlap, a stifl' fabric woven from jute, is made flexible, soft and absorbent by receiving the above described treatment.

The instances in which the inventicn introduces' new industrial effects and improvements, in the 4 `art of dealing with fiber, have been found so numerous and s'o varied that the describing of Rendering available for ne spinning certainkinds of fibers, for which only coarse spinning has heretofore been practicable, illustrative instances being found in pita, sisal, manila, New Zealand,

and many other-'fibers which are scientifically known to have valuable qualities but which have not been utilized because of difficulty in spinning.

The term pita used in this connection refers not only to the forty or so botanical varieties in whose name the word p ita occurs, but also specifically to the variety having no botanical name, so far as I know, which is found in the Magdalena-Valley in Colombia and -hasa very long,

fine ber hitherto practically unmanageable;

f Producing sub-divided` fiibrilized) without disproportionate reduction of strength,

illustrations being found in hemp, jute, flax, pit-a, sisal, ramie.

Dealing with difficult fibers at commercially practicable cost, in some cases where cost has heretofore been a prohibitive factor; and utilizing strong and less wastageto tow. in the case of some fibers which have heretofore been spun, a feature found particularly valuable with ramie; also with hemp and jute, which, however, have not heretofore been made into fine cloth.

Imparting a pronounced absorbent qualit v, of the order of absorbent cotton, to some inexpensive fibers hitherto having no such quality; producing also an observable increase of elasticity of the spun or woven product; removing characteristic individualvodor such as heretofore 4has persisted offensively in the unfibrilized fiber, and been subject to regeneration by moist air as in hemp, jute and flax; preserving and bringing out to view a beautiful native lustre of the fiber, in

4$01118 instances not realized heretofore.

Also, preparing the fiber befo're bleachingiso that it will retain permanently the whiteness produced by the bleaching.

An incident is that it enablesthe manufacture of the fiber to proceed with fewer steps, e. g. to' eliminate the customary washing and souring` before the usual bleaching, with saving of costs;

and another manufacturing benefit is the ren dering of the woven product free from shrinkage, obviating theusual cloth pre-shrinking opera,-

tionf because the invention incidentally preshrinks the fiber.

Other features are the rendering of the fiber immune to insect attackpthe softening of varieties called hard fiber, so that they become notably more flexible 'and pliable, and when in the mass are softer to the touch; and the introducing of kink or equivalent characteristic which makes certain fibers easily spinnable which heretoforeihave been unspinnable, or spinnable only with "difficulty, .or without holding power, of which ramie'is an illustration.

In some cases there is a substantial reduction of net over-all cost by.' the incidental production of valuable by-products, an instance of which is in cases where pectic bodies, boiled out, can'be utilized.

I claim as my invention: r l. Atpro'cess for liberation of plant fibrils comprising the immersing 'of a mass of decorticated natural fiber-bundles ina solution boiling in atmosphere, in whichsolution to of water there are about .2% to .5% (two-tenths to fivetenths of oneper cent) `,of neutral soap and about bonate, the 'said treatment continuing with erosion of lateral -cementitious connections' between cells in the fiber untilseparation of bers into fibrlllized fragments occurs.

2'. A process for liberation of plant brils comprising the preparing of a solution by putting,

into boiling water, of a 'comminutedmixture of neutralsoap about one-half. of one per cent ofthe water, and of sodium carbonate, about .4%

(four-tenths of one per cent) of the water; and, Iwhen these are well dispersed in the water, im-

4% (four-tenths of one per cent) of sodium carstanding between their ultimate cells, by a hot alkaliA aqueous solution in vwhich the strength of alkali is substantially that of a concentration -therein of one-third of one per centto one-half y of one per cent of carbonate, meanwhile 'z5/- protecting the cellulose of the fibrils, from degeneration 'by z'eaciziox with the alkali, by pro- .viding in the same solution an hydrophilic dispersion such as results from the introducing of neutral soap in quantity within the range' onefth of one per cent to one per cent of the weight of the solution.

4. A process as inclaim 3, in which the concentration of alkali is'substantially one-half of one per cent of sodium carbonate.

5. A process as in claim 3 in which the alkali characteristic is provided by introducing sal soda eroding reaction is 'being executed the solution is maintained in vigorous ebullition, is open to atmosphere, and `contains the fiber immersed.

9. A process as in claim 3, inlwhich the hydrophilic dispersion is made by putting the soap in nely divided form into water which is already boiling.

mately in the range of one-third of one per cent to one-half ot one per cent of the water, in which solution the ber is immersed, by the alkali of which solution covering matter is removed from the surface of the cellulose of the ilber; and further comprising the protecting that cellulose meanwhile from chemical degeneration by the alkali, by providing in the same solution an hydrophilic dispersion of a substance inert with respect to the cellulose but which substance the cellulose selectively adsorbs in preference to the alkali, such as results from the r`introducing of neutral soap in quantity within the range onefth of one per cent to one per-cent of the weight of the solution.

JOSEPH H. ESTES. 

